Java 死锁检测

package com.agileeagle.webgame.game.job;

import java.lang.management.ManagementFactory;
import java.lang.management.ThreadInfo;
import java.lang.management.ThreadMXBean;

/**
 * 死锁检测
 * Date: 2019/7/30.
 * Author:chongxin
 */
public class DeadlockCheck {
    private static final ThreadMXBean mbean = ManagementFactory.getThreadMXBean();

    public static void checkForDeadlocks() {
        long[] ids = findDeadlockedThreads();
        if (ids != null && ids.length > 0) {
            ThreadInfo[] threadInfo = mbean.getThreadInfo(ids, true, true);
            for (ThreadInfo info : threadInfo) {
                System.out.println(info);
            }
        }

    }

    private static long[] findDeadlockedThreads() {
        if (mbean.isSynchronizerUsageSupported()) {
            return mbean.findDeadlockedThreads();
        } else {
            return mbean.findMonitorDeadlockedThreads();
        }
    }
}

package com.agileeagle.webgame.game.job;

import java.util.Timer;
import java.util.TimerTask;

public class DeadLockDemo extends Thread {
    private static Object obj1 = new Object();
    private static Object obj2 = new Object();
    private boolean flag;

    public DeadLockDemo(boolean flag){
        this.flag = flag;
    }

    @Override
    public void run(){
        System.out.println(Thread.currentThread().getName() + "运行");

        if(flag){
            synchronized(obj1){
                System.out.println(Thread.currentThread().getName() + "已经锁住obj1");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized(obj2){
                    // 执行不到这里
                    System.out.println("1秒钟后，"+Thread.currentThread().getName()
                            + "锁住obj2");
                }
            }
        }else{
            synchronized(obj2){
                System.out.println(Thread.currentThread().getName() + "已经锁住obj2");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized(obj1){
                    // 执行不到这里
                    System.out.println("1秒钟后，"+Thread.currentThread().getName()
                            + "锁住obj1");
                }
            }
        }
    }

    public static void main(String[] args) throws InterruptedException {

        Thread t1 = new Thread(new DeadLockDemo(true), "线程1");
        Thread t2 = new Thread(new DeadLockDemo(false), "线程2");
        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            public void run() {
                DeadlockCheck.checkForDeadlocks();
            }
        }, 2000 , 1000);
        t1.start();
        t2.start();

    }
}